Auto-focus in a camera automatically focuses a camera lens on a three-dimensional scene, without the need for the camera user to manually focus the camera lens. There are many auto-focus schemes known in the art. A traditional auto-focus scheme searches for the peak of the auto-focus curve (e.g., peak-hold-integrate method, hill-climbing, etc.). Typically, there is a different auto-focus curve for different camera optical settings (camera type, lens type, aperture, focal length, shutter speed, film or sensor speed, etc.). In addition, the auto-focus curve will be a function of the scene itself and the region analyzed. In one embodiment, a camera employs a hill climbing scheme that computes the auto-focus curve from image gradients. As the region of analysis becomes more and more in focus, the image gradients will become larger and larger. The objective of the auto-focus algorithm is to reach the peak of the auto-focus curve using a minimum number of camera focus positions. In general, hill-climbing auto-focus schemes require a large number of pictures of the three-dimensional scene in order to converge to the desired focus position.